Layer-by-layer (LbL) assembly allows one to create multifunctional films on surfaces while maintaining the bulk properties of the individual surfaces [1]. The method relies on sequential adsorption of polymers onto bulk surfaces from solution, giving rise to complex multifunctional, multilayered films. LbL assembly is simple to implement and offers extensive control over film properties and composition during stepwise adsorption of components.
Although the vast majority of LbL films are built from polyelectrolytes via electrostatic interaction between layers, more recently LbL films have been made with hydrogen bonding of polymers [2], and other building blocks such as inorganic nanoparticles, giving access to even greater control of chemical and physical properties of LbL films.
In principle, LbL assembly can be performed on a wide variety of substrates, including noble metals (Au, Pt, etc.), oxides (quartz, Si, TiO2, mica etc.), and synthetic polymers (polyethylene terephthalate (PET), poly(methyl methacrylate) (PMMA), polyetherimide, etc.) [3,4]. In practice, however, forming well-ordered LbL layers on many polymeric surfaces has proven challenging [5-7], and LbL assembly on hydrophobic polymers such as poly(tetrafluoroethylene) (PTFE), and polyethylene (PE) often requires aggressive ‘priming’ methods such as plasma treatments [5,7], oxidative chemical reactions (piranha/persulfonation)[8,9], or polymeric adsorption[6,10,11].
Accordingly, a need exists for catechol-functionalized polymers for use in LbL assembly of multifunctional films wherein the polymers allow substrate-independent LbL assembly.